With the development of the elevator technology, the usage of elevator transport equipments, such as vertical elevators, automatic escalators, automatic sidewalks, and the like, has become more and more popular and more and more widespread. Accordingly, the problem of how to realize a safety brake on various kinds of elevator carrying equipment has been gradually highlighted.
For vertical elevators, in normal situations, the brakes are breaking with zero speed after reaching the target floor, namely static brake; and when an abnormal condition occurs and an urgent brake is required, a breaking force which is too large or too small brake force can be dangerous to the person(s) in an elevator. A breaking force that is too large will make the car of the elevator decelerate too quickly, which may injure the person(s) in the car. A breaking force that is too small can't achieve the goal of safety brake, and may even cause serious accidents, such as that the elevator collapsing to the ground or hitting the ceiling. This is a widespread safety problem existing in elevator brake systems.
For escalators or sidewalks, when an abnormal situation happens and emergency breaking is needed, if the breaking force is too large, there is also a risk of causing the passenger(s) to fall, which can lead to injuries.
In addition, for an existing elevator without a machine room, when the elevator stops under abnormal conditions and while there are no people locked in the car, the rescue operation for manually releasing the break is extremely inconvenient. Due to the narrow stairway space, a worker can't operate the brake handle directly, and has to release the brake using a remote operating mode. Since corresponding mechanism components may have not been used in a long period of time, which can result in the problems with corrosion of mechanical transmission mechanism or a mechanical transmission device having a resistance that is too large, the remote operating mode may lead to a dangerous situation where the brake does not work again after the brake is released manually.
In view of this, when an elevator goes into an abnormal condition and emergency breaking is needed, it is practically important to realize a brake control system that can brake dynamically and effectively to safely decelerate the elevator carrying equipment, and a control mechanism with a reliable manual brake release measure in an emergency is also essential. But unfortunately, up to now, the elevator industry has not developed such a brake control system or control mechanism. Thus, the above-mentioned significant security risk exists in elevator brake systems has not been eliminated and solved.